Method for the manufacture of superphosphates



Feb. 21, 1939. H. LOISEAU ET AL I METHOD FOR THE MANUFACTURE OFSUPEBPHQSPHAIES Filed Nov. 16, 1957 4 Sheets-Sheqt 1 Whoa chute v Feb.21, 1939. H LOISEAU ET AL I 2,148,209

METHOD FOR THE MANUFACTURE OF SUPERPHOSPHAIES Filed Nov. 16, 193'? 4Sheets-Sheet 2 Feb. 21', 1939. H. LOlSEAU ET AL 2,148,209

METHOD FORTHE MANUFACTURE OF SUPERPI-IQSPHATES ,Filed Nov. 16, I937 4Sheets-Sheet 3 III! II HJLOISEAU ET AL 2,148,209

METHOD FOR THE MANUFACTURE OF SUPERPHOSPHATES Filed Nov. 16, 1937 4Sheets-Sheet 4 )7 W an 1 Patented Feb. 21, 1939 METHOD FOR THEMANUFACTURE OF SUPEBPHOSPHATES Henri Loiseau and Georges-Gartigny,Ertvelde-- Rieme, Belgium, assignors to Compagnie Nationale de MatieresColorantes ct Manufactures de Produits Chimiques du Nord Reunion]Etablissements Kuhlmann, Paris, France. a corporation, of FranceApplication November 10, 1937, Serial No. 174,252 i In Germany'December16, 1935 2 Claims. (Cl. 71-40) Our invention has for its object aperfectly continuous method of manufacture of superphosphates from thefeeding of the components (crushed phosphate and phosphoric or sulphuricacid) up to the storing of the final product.

' Our method is chiefly characterized by the fact that the componentsare fed to a mixer in predetermined proportions and are transformed insaid mixer into a sort of emulsion which falls in a continuous manner onto a conveyor comprising one or morebelts on which the material becomessolid, is disintegrated, begins drying and is brought to its final drystate.

Our invention also covers the general arrangement used for executingthe. method, said arrangement including different interesting details tobe disclosed hereinafter. v A form of execution of the arrangementchosen by way of example has been shown in accompanying drawings.

Fi 1 is a diagrammatical side view of the whole arrangement.

I'Pig 2 is a. diagrammatical cross-section at a larger scale, throughline 2--2 of Fig. 1. Figs. 3-4-5 relate to the mixer of which Fig. 3 isan axial cross-sectional vertical view, .Fig. 4 at plan view and Fig. 5a cross-section through line 5-5 of Fig. 3. 1

Fig. 6 is a side view, partly sectional of the vi-- bratory controlmeans of the edges of the conveyor belt.

Figs. '7 and 8 relate to the disintegrator of which Fig. '7 is an, axialsectional view and Fig. 8 an end view.

,35 The crushedphosphate is introduced into a 45 the distribution ofwhich is ensured by any known measuring devi'ce 8 such as a gauge of theso-- called Howard type;

The weighing apparatus 3 and the measuring device I are, connectedthrough rigid control 50 means with a common motor provided with speedreducing. means wherebyqthe predetermined proportion of the componentsis held constant.

In thecasewhere the density of the acid were to vary, the device 3 wouldbe adjusted corre- 55 spondingly. I

From the mixer 6 described hereinafter, the emulsion formed by the acidand the pulverulent phosphate, falls on an element ll of a conveyor beltthe tension of which is ensured by a movable pulley I 2 on which acounterweight i3 exerts a 5 tensioning action.

The emulsion becomes progressively solid on this belt the length ofwhich is sufllcient-for the emulsion to be capable of disintegrationwhen the product arrives on to the disintegrator il- 10 describedhereinafter.

The disintegrated product falls then on to the elements l5, it of aconveyor belt where it begins being submitted to a drying in the open.It is discharged into the elevator I! which leads it into 15 the finaldrier not shown.

The mixer (Figs. 3 to 5) is constituted by a cylindrical-receiver openat its upper part and along the axis of which is arranged airotary cientmixing before discharge of the product. 30'

To this end for instance, the funnel which extends into the telescopictube 5 leads to the opening drawn in dotted lines in-Fig. 5, whichopening lies a few centimeters above the arm 22. In

principle the pipe 1 feeding the acid will open also above the arm 22, alittle more towards the inside of the mixer and the jet is directedtowards the central shaft I! so as to prevent any accumulation of dirtthereon.

By reason of the phosphate feed drawing-air 40 along with it and of thehigh speed of the aura ably shaped turbine, we, obtain an emulsion ofphosphate in the acid. v

The element ii of the conveyor belt is carried, from place to place, onrollers '25 which in the vicinity of the mixer 8 are much closer to eachas other so as to ensure perfect horizontality of the upper strand ofthe belt.

Other rollers 26, spaced much more apart, v carry the lower strand. Asthey are in contact with the upper surface of the belt, they becomedirty. For cleaning them, we use spring urged blades 21. The filmremoved by these blades falls on to the belt element l5 arrangedimmediately underneath. is

Inthevicinityofthestirreros'mixertthe emulsion is still very liquid andit is necessary to prevent the emulsion from falling off the belt; tothis end we usefianges separate from the belt,

- which maybe constituted for instance by wooden bars I. with rubberlinings II in fiuidtight contact with the belt.

To prevent these flanges from becoming dirty and clogged, it is usefulto give them a horizontal vibratory motion. To this end (Fig. 6) theyare held by spring blades 8i and are mechanically integral with rollerbearings ll which provide a passage for a shaft a carrying an eccentricweight it and connected through an elastic coupling II with the shaft 8.of an electric motor. This motor rotates'in a direction such that animagi-' ing solidified product is constituted (Figs. 1, 'l and 8) by twocircular flanges l1 rigidly secured to the shaft SI and interconnectedby the stays 30. A series of thin steel wires 4| connect the peripheriesof the two flanges together. Their tension is ensured by nuts arrangedat their ends. The whole forms thus a squirrel cage arranged above thebelt I so that the cylinder described by the outer generating line ofthe steel wires is tangent to a plane spaced by about 1mm. withreference to and abovethe belt. heferably the distintegrator is placedin the vicinity of the pulley I! over which the belt changes itsdirection and the direction of rotation of the disintegrator is suchthat it furthers the fall of the disintegrating product on the beltelement ll arranged underneath belt II. This provides an ungroundproduct appearing under the shape of small flakes.

The wires are not soiled or fouled to the least extent. This is due tothe fact that in spite of their tension they are slightly sagged duringoperation and after same they return suddenly into their originalposition. The vibration thus proout cutting.

duced loosens the particles which may have stuck to'the wires.

The subdivided product, still very soft, must assume sumcientconsistency or firmness for allowing its passage through the drierwithout agglom- 5 erating into lumps. This prior drying is provided onthe lower belt elements ll-it.

Preferably as shown in Fig. 2 the upper strand of these belt elements isslightly concave so as to avoid any fall of the product carried thereby.This concavity is obtained very' simply, for instance by using assupporting rollers three-element rollers the central element of which orcentral roller i3 is alone horizontal, while the lateral elements, 44are slopingly arranged.

However our invention is by no means limited to the conveyor meansdescribed. For instance at its outlet from the mixer, the emulsion orpulpy material may fall on a wide belt the cross-section of which isincurved so as to form a sort of a m ing, under a common control,powdered raw, phosphate rock and a mineral acid selected from the groupconsisting of sulphuric acidand phosphoric acid to a mixer in quantitieswhich merely suihce to yield a thin layer upon {continuously 5 movingsurface when discharged thereupon, submitting the quantities of saidpowdered rock and of said acid to a quiclr centrifugal action in thepresence of air whereby said air is drawn into the mixture and to form alight foam, continuously discharging said foam upon the moving surfacein a thin layer, solidifying the reaction mixture and. thendisintegrating the same during the course of travel of said movingsurface.

2. A method according to claim l'in which the distintegration is.effected by beater action with- HENRI LOIBEAU. GEORGES CAR'I'IGNY.

} superphosphates consisting in continuously feed-Wu

